Optical sensor, optical sensor assembly and monitoring device

ABSTRACT

An optical sensor ( 100 ) comprises: a holding sleeve ( 11 ); a fixed ferrule ( 12 ) fixedly mounted in said holding sleeve ( 11 ); a movable ferrule ( 13 ) movably mounted in said holding sleeve ( 11 ), a predetermined distance existing between a first movable end of said movable ferrule ( 13 ) and a first fixed end of said fixed ferrule ( 12 ) in said holding sleeve ( 11 ); a reflection part ( 14 ) arranged at a second movable end of said movable ferrule ( 13 ) opposite to said first movable end, for reflecting light entering the movable ferrule ( 13 ); and an actuation part ( 15 ), said actuation part ( 15 ) being constructed to drive said movable ferrule ( 13 ) to move so that said first movable end moves towards said first fixed end. An optical sensor assembly and a monitoring device comprising the optical sensor ( 100 ), or another sensor ( 1012 ) can remotely detect a mechanical movement in a passive mode. A first reflector ( 14, 1016 ) is configured to provide a first reflected optical signal. The sensor ( 100, 1012 ) is connected to the first reflector and has a first position and a second position, the second position configured to attenuate the first reflected optical signal more than the first position. The sensor is configured to move between the first and second positions in response to a monitored parameter ( 1018 ).

CROSS-REFERENCE TO RELATED APPLICATION(S)

This application claims priority to U.S. Patent Application Ser. No.61/822,655 filed on 13 May 2013, and to Chinese Patent Application No.201310223485.6 filed on 6 Jun. 2013, the disclosures of which areincorporated herein by reference in their entireties.

TECHNICAL FIELD

The present invention relates to an optical sensor, in particular anoptical sensor capable of sensing mechanical movement, and an opticalsensor assembly and a monitoring device having the optical sensor.

BACKGROUND ART

A variety of sensors capable of sensing mechanical movement have beendeveloped. However, if a result sensed by a sensor is transmitted to amonitoring room far away from a detection site, for example when thedetection site is more than hundreds of or thousands of meters away fromthe monitoring room, the detection result is generally required to betransmitted to the monitoring room through an electrical wire.

For example, in an optical cable communication system, a field opticalcross-connecting box relatively far away from places of activity ofpeople is generally used to protect intermediate components such as anoptical fiber connector, distributor and adapter in the optical cablecommunication system. In some cases, the cross-connecting box may beopened accidentally, or opened due to technical personnel or engineeringpersonnel forgetting to close it, or opened due to being impacted orstolen. In these unwanted abnormal cases of opening, the opticalcross-connecting box cannot provide protection for an optical fiberdevice therein.

Therefore, there is a need for a sensor which can detect the opening orclosure of an optical cross-connecting box at any time, and a detectionresult is required to be transmitted to a monitoring room far away fromthe optical cross-connecting box. However, since the opticalcross-connecting box is not provided with a power supply device, it isnot suitable to use an electric sensor and to transmit a sensed electricsignal through an electrical wire.

SUMMARY OF THE INVENTION

A technical problem solved by the present invention is to provide anoptical sensor and an optical sensor assembly comprising the opticalsensor, which can remotely detect mechanical movement in a passive mode.

The present invention further provides a monitoring device comprisingthe optical sensor assembly, for remotely monitoring a mechanicalposition of a certain part of a monitored object.

According to an embodiment of an aspect of the present invention, anoptical sensor is provided which comprises: a holding sleeve; a fixedferrule fixedly mounted in said holding sleeve; a movable ferrulemovably mounted in said holding sleeve, a predetermined distanceexisting between a first movable end of said movable ferrule and a firstfixed end of said fixed ferrule in said holding sleeve; a reflectionpart arranged at a second movable end of said movable ferrule oppositeto said first movable end, for reflecting light entering the movableferrule; and an actuation part, said actuation part being constructed todrive said movable ferrule to move so that said first movable end movestowards said first fixed end.

The above optical sensor further comprises a reset device, which drivessaid movable ferrule to move against the force of said reset device.

In the optical sensor as described above, said reflection part is areflection face formed on the second movable end of said movableferrule. Said reflection face provides a reflection characteristicindependent of wavelength. Said reflection face can also provide aselective waveband reflection characteristic dependent on wavelength.

In the optical sensor as described above, said reflection part is formedon said actuation part, and is in sealed connection with said secondmovable end.

In the optical sensor as described above, a limiting part is arranged onone of said movable ferrule and the actuation part, and said limitingpart is constructed to limit the distance of movement of said movableferrule.

In the optical sensor as described above, the end surfaces of said firstfixed end and said first movable end are constructed to be parallel witheach other and form an angle relative to an axis of the holding sleeve.

In the optical sensor as described above, the end surfaces of said firstfixed end and said first movable end are inclined by 5°-10° relative tothe axis of the holding sleeve.

Said optical sensor further comprises: a main body frame, said holdingsleeve being arranged in said main body frame; and a guide frame mountedon said main body frame, said actuation part being movably mounted onsaid guide frame.

In the optical sensor as described above, said actuation part isprovided with a guide protrusion, and said guide frame is provided witha guide groove matching with said guide protrusion.

The above optical sensor further comprises a housing, and said main bodyframe is mounted in said housing.

The above optical sensor further comprises a positioning frame mountedbetween said housing and said guide frame.

In the optical sensor as described above, said housing is connected tosaid actuation part through a flexible connection part so that saidflexible connection part moves with said actuation part.

According to an embodiment of a still further aspect of the presentinvention, an optical sensor assembly is provided which comprises: anoptical sensor as described in any one of the embodiments above; and anoptical cable transmission device, constructed to be optically coupledto a second fixed end of said fixed ferrule, for transmitting lightincident to said fixed ferrule and light reflected from said reflectionpart.

In the optical sensor assembly as described above, a first end of anoptical cable of said optical cable transmission device is provided witha first optical fiber connector, and a second end of the optical cableof said optical cable transmission device is directly optically coupledwith the second fixed end of said fixed ferrule.

In the optical sensor assembly as described above, a first end of anoptical cable of said optical cable transmission device is provided witha first optical fiber connector, and a second end of the optical cableof said optical cable transmission device is optically coupled with thesecond fixed end of said fixed ferrule through a second optical fiberconnector.

According to an embodiment of a further aspect of the present invention,a monitoring device is provided which comprises: at least one opticalsensor assembly as described in any one of the embodiments above, theoptical sensors of said optical sensor assembly being respectivelymounted to at least one monitored object; and an optical time domainreflectometer, constructed to emit a main beam towards said opticalsensors through an optical cable transmission device of the opticalsensor assembly and receive a reflected beam reflected from said opticalsensors, the optical path distances between said optical time domainreflectometer and the optical sensors being different from one another.

The monitoring device as described above further comprises: a shunt,constructed to separate at least one detection beam out of the main beamfrom said optical time domain reflectometer, each detection beam beingtransmitted to a corresponding optical sensor assembly.

The monitoring device as described above further comprises a splitter,which is constructed to split said detection beam into multipledetection sub-beams, each detection sub-beam being transmitted to acorresponding optical sensor assembly.

In the monitoring device as described above, said monitored objects aredivided into multiple groups, and one shunt and at least one opticalsensor assembly are arranged for each group of monitored objects.

Said monitoring device further comprises an optical switch, which isconstructed to control one of said shunts to come into an operatingstate.

In the monitoring device as described above, said monitored objects aredivided into multiple groups and at least one optical sensor assembly isarranged for each group of monitored objects; said monitoring devicefurther comprises multiple splitters connected in series, wherein eachsplitter splits a detection beam from a previous stage into a maindetection beam and a detection sub-beam, and each splitter is arrangedin a propagation path of the detection main beam, each optical sensorreceiving a corresponding detection sub-beam.

In the monitoring device as described above, the light flux ratio of themain detection beam and detection sub-beam output from each splitter is20:80-1:99.

In the monitoring device as described above, the monitored objectincludes a field optical cross-connecting box.

According to an optical sensor, an optical sensor assembly and amonitoring device of the embodiments of the present invention asdescribed above, the movement of an actuation device results in thecontact of the end surfaces of the fixed ferrule and movable ferrule, sothat a beam from the fixed ferrule is incident to the movable ferrule,and the incident beam is further reflected to the optical time domainreflectometer, so as to remotely detect mechanical movement in a passivemode and monitor a mechanical position of a certain part of themonitored object.

In accordance with aspects of the present disclosure, a passive opticalsensor system is provided. In general, a reflected optical signal isattenuated in response to a monitored parameter, so that analyzing thereflected optical signal provides an indication of the parameter basedupon the attenuation. In one example, a sensor system and methodincludes a first reflector configured to provide a first reflectedoptical signal. A sensor is connected to the first reflector and has afirst position and a second position, the second position configured toattenuate the first reflected optical signal more than the firstposition. The sensor is configured to move between the first and secondpositions in response to a monitored parameter, thus changing theattenuation of the first reflected signal to provide an indication ofthe monitored parameter. The sensor system can be employed, for example,to monitor parameters of one or more enclosures.

DESCRIPTION OF THE DRAWINGS

The present invention will be described in more detail with reference tothe drawings, in which:

FIG. 1 shows a sectional schematic view of an optical sensor accordingto the present invention;

FIG. 2A shows a sectional schematic view of the optical sensor shown inFIG. 1 when an actuator is not compressed;

FIG. 2B shows a sectional schematic view of the optical sensor shown inFIG. 1 when the actuator is compressed;

FIG. 3 shows a perspective schematic view of an optical sensor accordingto a first exemplary embodiment of the present invention;

FIG. 4 shows a partially exploded schematic view of the optical sensorshown in FIG. 3;

FIG. 5 shows a perspective schematic view of the housing and main bodyframe of the optical sensor shown in FIG. 4;

FIG. 6 shows a perspective schematic view of the main body frame mountedin the housing in FIG. 5;

FIG. 7 shows a sectional schematic view vertically sectioned through theoptical sensor shown in FIG. 3 along the central axis, with the actuatornot compressed;

FIG. 8 shows a sectional schematic view horizontally sectioned throughthe optical sensor shown in FIG. 3 along the central axis, with theactuator not compressed;

FIG. 9 shows a perspective schematic view of an optical sensor accordingto a second exemplary embodiment of the present invention;

FIG. 10 shows a sectional schematic view horizontally sectioned throughthe optical sensor shown in FIG. 9 along the central axis, with theactuator not compressed;

FIG. 11 shows a sectional schematic view horizontally sectioned throughthe optical sensor shown in FIG. 9 along the central axis, with theactuator compressed;

FIG. 12A shows a schematic view of a monitoring device according to afirst exemplary embodiment of the present invention; FIG. 12B shows acurve diagram of light intensity acquired at an optical time domainreflectometer as a function of distance when the monitoring device shownin FIG. 12A operates;

FIG. 13A shows a schematic view of a monitoring device according to asecond exemplary embodiment of the present invention; FIG. 13B shows acurve diagram of light intensity acquired at an optical time domainreflectometer as a function of distance when the monitoring device shownin FIG. 13A operates;

FIG. 14A shows a schematic view of a monitoring device according to athird exemplary embodiment of the present invention; FIG. 14B shows acurve diagram of light intensity acquired at an optical time domainreflectometer as a function of distance when the monitoring device shownin FIG. 14A operates;

FIG. 15A shows a schematic view of a monitoring device according to afourth exemplary embodiment of the present invention; FIG. 15B shows acurve diagram of light intensity acquired at an optical time domainreflectometer as a function of distance when the monitoring device shownin FIG. 15A operates;

FIG. 16A shows a schematic view of a monitoring device according to afifth exemplary embodiment of the present invention; FIG. 16B shows acurve diagram of light intensity acquired at an optical time domainreflectometer as a function of distance when the monitoring device shownin FIG. 16A operates;

FIG. 17 shows a schematic block diagram of a monitoring system formonitoring multiple monitored points by using the monitoring deviceaccording to the present invention;

FIG. 18 is a block diagram illustrating aspects of an example of asensor system in accordance with the present disclosure;

FIG. 19 is a block diagram illustrating aspects of another example of asensor system in accordance with the present disclosure;

FIG. 20 is a block diagram illustrating aspects of an example of anenclosure monitoring system in accordance with the present disclosure;

FIG. 21 is a chart illustrating example optical time-domainreflectometer signals of a monitoring system such as that shown in FIG.20;

FIGS. 22A-22C are block diagrams illustrating examples of enclosure andsensor system configurations in accordance with the present disclosure;

FIG. 23 is a block diagram conceptually illustrating an example of asensor in accordance with the present disclosure, situated in a firstposition;

FIG. 24 is a block diagram showing the example sensor of FIG. 23situated in a second position;

FIG. 25 is a chart illustrating further example optical time-domainreflectometer signals of a monitoring system such as that shown in FIG.20;

FIG. 26 is a block diagram conceptually illustrating an example of asensor system in accordance with the present disclosure, configured tomonitor the parameter of enclosure intrusion;

FIG. 27 is a block diagram illustrating aspects of another example of asensor system in accordance with the present disclosure;

FIG. 28 is a chart illustrating example optical time-domainreflectometer signals of a sensor system such as that shown in FIG. 27;

FIG. 29 is a block diagram illustrating aspects of another example of asensor system in accordance with the present disclosure; and

FIG. 30 is a chart illustrating example optical time-domainreflectometer signals of a sensor system such as that shown in FIG. 29.

DETAILED DESCRIPTION

Although the present invention will be fully described with reference tothe drawings including preferred embodiments of the present invention,before the description, it is to be understood that those skilled in theart can modify the utility model described herein and achieve thetechnical effect of the present invention. Therefore, it is necessary tounderstand that the description above is a general disclosure for thoseskilled in the art and the content thereof is not intended to limit theexemplary embodiments described in the present invention.

FIG. 1 shows a sectional schematic view of an optical sensor 100according to the present invention. According to the overall inventiveconcept of the present invention, the optical sensor 100 comprises: aholding sleeve 11; a fixed ferrule 12 for optically coupling with anoptical fiber of an optical cable and fixedly mounted in the holdingsleeve 11; a movable ferrule 13 movably mounted in the holding sleeve11, a predetermined distance D1 existing between a first movable end ofsaid movable ferrule 13 and a first fixed end of the fixed ferrule 12 inthe holding sleeve 11; a reflection part 14 arranged at a second movableend of said movable ferrule 13 opposite to said first movable end, forreflecting light entering the movable ferrule 13; and an actuation part15, said actuation part 15 being constructed to drive the movableferrule 13 to move so that the first movable end of the movable ferrule13 comes into contact with the first fixed end of the fixed ferrule 12,so as to allow an optical fiber hole 121 of the fixed ferrule 12 tocontact with an optical fiber hole 131 of the movable ferrule 13.

The optical sensor 100 further comprises a reset device 16, said resetdevice 16 being arranged between the movable ferrule 13 and theactuation part 15, and when the actuation part 15 contracts towards theinterior of the optical sensor 100 due to a pressure being applied, theactuation part 15 drives the movable ferrule 13 to move against theforce of the reset device 16. The reset device 16 can be a springsurrounding the movable ferrule 13, and can also be a reset device whosemovement is based on magnetic force or another device capable ofautomatically driving the actuation part to reset.

Generally, as shown in FIG. 2A, when the actuation part 15 is in anuncompressed state, due to the action of the reset device 16, apredetermined distance D is kept between the first movable end of themovable ferrule 13 and the first fixed end of the fixed ferrule 12 inthe holding sleeve 11, so that a beam of light from the fixed ferrule 12will freely diverge at the first fixed end while only a very small partof the beam can be incident to the movable ferrule and reflected back tothe fixed ferrule by the reflection part 14.

On the other hand, as shown in FIG. 2B, when the actuation part 15 iscompressed, the actuation part 15 overcomes the acting force of thereset device 16 and drives the movable ferrule 13 to move towards thefixed ferrule 12, so that the first movable end of the movable ferrule13 comes into contact with the first fixed end of the fixed ferrule 12,so as to allow the optical fiber hole 121 of the fixed ferrule 12 tocontact with the optical fiber hole 131 of the movable ferrule 13. Thus,most of the beam from the fixed ferrule 12 will be incident to themovable ferrule and reflected back to the fixed ferrule 12 by thereflection part 14. The reflected beam can be transmitted to an opticaltime domain reflectometer through an optical cable transmission device,so as to detect the condition where the actuation part 15 is driven(which will be described in detail hereafter).

According to the optical sensor 100 of the present invention, thereflection part 14 can be a flat reflection face formed on the secondmovable end of the movable ferrule 13, such as by grinding, polishingtreatment, film coating, attaching a reflector mirror and the like, forreflecting the beam incident to the movable ferrule 13 and emitting areflected beam from the movable ferrule 13. In one embodiment, thereflection face can provide a reflection characteristic independent ofwavelength. In another embodiment, the reflection face can also providea selective waveband reflection characteristic dependent on wavelength.In an alternative embodiment, the reflection part 14 is a smooth andflat reflection face formed on the actuation part 15 and in sealedconnection with the second movable end of the movable ferrule 13, andthus can also reflect a beam incident to the movable ferrule 13 and emita reflected beam from the movable ferrule 13.

Furthermore, a limiting part 17 is arranged on the movable ferrule 13,the limiting part 17 being constructed to limit the distance of movementof said movable ferrule 13. The limiting part 17 can be used to preventthe movable ferrule 13 from excessively pressing the fixed ferrule 12when the actuation part 15 contracts, and from separating from theoptical sensor 100 when the actuation part 15 extends due to the actionof the reset device 16. It can be understood that the limiting part canalso be arranged on the actuation part 15.

According to the optical sensor 100 of the present invention, the endsurfaces of the first fixed end of the fixed ferrule 12 and of the firstmovable end of the movable ferrule 13 are constructed to be parallelwith each other and form an angle relative to the axis of the holdingsleeve 11. Preferably, the end surfaces of the first fixed end and thefirst movable end are inclined by 5°-10°, more effectively 8°, relativeto the axis of the holding sleeve 11. This inclined structurefacilitates a tight contact between the end surfaces of the first fixedend and the first movable end, and minimizes light loss when a beam istransmitted between the fixed ferrule 12 and the movable ferrule 13.However, the present invention is not limited to such an inclined endsurface, and those skilled in the art can understand that theinclination of the end surfaces of the first fixed end and first movableend relative to the axis of the holding sleeve 11 can be set to beperpendicular, or they have curved surface structures complementary toeach other, as long as a beam is maximally transmitted between the fixedferrule and movable ferrule after they are in contact.

FIGS. 3-8 show an optical sensor 200 according to a first exemplaryembodiment of the present invention, the optical sensor 200 of the firstembodiment having the same inventive concept and basic structure as theoptical sensor 100. Particularly, referring to FIGS. 3-8, the opticalsensor 200 comprises: a holding sleeve 21; a fixed ferrule 22 foroptically coupling with an optical fiber of an optical cable and fixedlymounted in the holding sleeve 21; a movable ferrule 23 movably mountedin the holding sleeve 21, a predetermined distance D2 existing between afirst movable end of said movable ferrule 23 and a first fixed end ofthe fixed ferrule 22 in the holding sleeve 21; a reflection part 24arranged at a second movable end of said movable ferrule 23 opposite tosaid first movable end, for reflecting light entering the movableferrule 23; and an actuation part 25, said actuation part 25 beingconstructed to drive the movable ferrule 23 to move so that the firstmovable end of the movable ferrule 23 comes into contact with the firstfixed end of the fixed ferrule 22. The optical sensor 200 furthercomprises a reset device 26, said reset device 26 being arranged betweenthe holding sleeve 21 and the actuation part 25, and when the actuationpart 25 contracts towards the interior of the optical sensor 200 due toa pressure being applied, the actuation part 25 drives the movableferrule 23 to move against the force of the reset device 26.

The optical sensor 200 of the first embodiment further comprises a mainbody frame 27 and a guide frame 28. The holding sleeve 21 is fixedlyarranged in the main body frame 27, the guide frame 28 is mounted on themain body frame 27, and the actuation part 25 is movably mounted on theguide frame 28. Particularly, the actuation part 25 passes through athrough hole 282 formed on an end part 281 of the guide frame 28, and aprotruding limiting part 251 arranged on the actuation part 25 isarranged on the inner side of the end part 281 so as to prevent theactuation part 25 from moving completely out of the guide frame 28, thelimiting part 251 is provided with a guide protrusion 252, and saidguide frame 28 is provided with a guide groove 283 matching the guideprotrusion 252. As such, with the cooperation of the guide protrusion252 and guide groove 283, the actuation part 25 pushes the movableferrule 23 to move axially and rotation of the actuation part 25 and themovable ferrule 23 is prevented.

The optical sensor 200 further comprises a housing 29, the main bodyframe 27 being mounted in the housing 29. Referring to FIGS. 6-8, themain body frame 27 comprises: a base part 271 mounted on the housing 29;a sleeve holder 272 extending from the base part 271, the holding sleeve21 being held in the sleeve holder 272; and two opposite extension arms273, the sleeve holder 272 being arranged between the two extension arms273. An engagement protrusion 274 protruding inwards is formed on a freeend of the extension arm 273 and, correspondingly, an engagement groove284 is formed on the guide frame 28. After a spring as the reset device26 is sheathed on the movable ferrule 23 and the actuation part 25 isallowed to extend out of the interior of the guide frame 28 via thethrough hole 282, the guide frame 28 can be inserted into the housing 29and the engagement protrusion 274 is engaged with the engagement groove284, so as to hold the guide frame 28 in the housing 29. A positioningframe 285 can be further mounted between the housing 29 and the guideframe 28, to stably mount the guide frame 28 inside the housing 29. Itcan be understood that the positioning frame 285 can also be omitted andsome positions on the guide frame 28 are constructed to be in directcontact with the interior of the housing 29, so that the guide frame 28can also be held inside the housing 29.

Furthermore, a mounting part 291 is arranged on the outside of thehousing 29, and a mounting hole 292 is arranged on the mounting part291. As such, the optical sensor 200 can be mounted onto a monitoredobject such as an optical cross-connecting box arranged in the field,using a bolt structure.

FIGS. 9-11 show an optical sensor 300 according to a second exemplaryembodiment of the present invention, the optical sensor 300 of thesecond embodiment having the same inventive concept and basic structureas the optical sensor 100. Particularly, referring to FIGS. 9-11, theoptical sensor 300 comprises: a holding sleeve 31; a fixed ferrule 32for optically coupling with an optical fiber of an optical cable andfixedly mounted in the holding sleeve 31; a movable ferrule 33 movablymounted in the holding sleeve 31, a predetermined distance existingbetween a first movable end of said movable ferrule 33 and a first fixedend of the fixed ferrule 32 in the holding sleeve 31; a reflection part34 arranged at a second movable end of said movable ferrule 33 oppositeto said first movable end, for reflecting light entering the movableferrule 33; and an actuation part 35, said actuation part 35 beingconstructed to drive the movable ferrule 33 to move so that the firstmovable end of the movable ferrule 33 comes into contact with the firstfixed end of the fixed ferrule 32. The optical sensor 300 furthercomprises a reset device 36, said reset device 36 being arranged betweenthe holding sleeve 31 and the actuation part 35, and when the actuationpart 35 contracts towards the interior of the optical sensor 300 due toa pressure being applied, the actuation part 35 drives the movableferrule 33 to move against the force of the reset device 36.

The optical sensor 300 of the second embodiment has a main body frame 37and a guide frame 38 with the same structure as the main body frame 27and the guide frame 28 of the optical sensor 200 of the firstembodiment, and a detailed description thereof is omitted herein.

In the optical sensor 300 of the third embodiment, the main body frame37 is mounted in a housing 39 made from a heat shrink material. Thehousing 39 comprises a flexible connection part 391, and said flexibleconnection part 391 crosses over the outer side of the guide frame 38and is connected to the actuation part extending out of the guide frame38, so that the flexible connection part 391 moves with the actuationpart 35. As such, the flexible connection part 391 can effectively sealthe interior of the optical sensor 300 to prevent dust, moisture andother impurities from entering the optical sensor 300, so as to protectthe optical sensor from the external environment (such as humidity,pollution and other factors). Furthermore, the flexible connection part391 has elasticity, and when a pressure pressing the actuation part 35is removed, the actuation part 35 can be restored to an original stateby the elastic force of the flexible connection part 391. Therefore, inan alternative embodiment, the flexible connection part 391 can be usedas a reset device, and the spring arranged between the holding sleeve 31and the actuation part 35 can be omitted.

According to an embodiment of a further aspect of the present invention,an optical sensor assembly is provided which comprises: the opticalsensors 100, 200 and 300 of the embodiments described above; and anoptical cable transmission device 101, constructed to be opticallycoupled to the second fixed ends of the fixed ferrules 12, 22 and 32,for transmitting light incident to the fixed ferrules 12, 22 and 32 andlight reflected from the reflection parts 14, 24 and 34.

Furthermore, the optical cable transmission device 101 comprises anoptical cable 102, a first end of the optical cable 102 is provided witha first optical fiber connector 103, and a second end of the opticalcable 102 of said optical cable transmission device 101 is directlyoptically coupled with the second fixed end of the fixed ferrules 12, 22and 32. Referring to FIGS. 7, 8, 10 and 11, the second fixed ends of thefixed ferrules 22 and 32 are provided with a strain relieve device 221and an optical fiber fixing assembly, and by means of the strain relievedevice 221 and the optical fiber fixing assembly, the optical fiber ofthe optical cable can be connected to the second fixed ends of the fixedferrules 22 and 32 in such a way as described for the connection of anoptical fiber and a ferrule in an optical fiber connector (such as an SCconnector, an LC connector) having an optical fiber ferrule in the priorart.

In an alternative embodiment, the first end of the optical cable of theoptical cable transmission device is provided with a first optical fiberconnector, and the second end of the optical cable of said optical cabletransmission device is optically coupled with the second fixed end ofsaid fixed ferrule through a second optical fiber connector. The secondfixed end of the fixed ferrule can be detachably connected with thesecond optical fiber connector (such as an SC connector or an LCconnector) having an optical fiber ferrule in such a way as describedfor the connection between an optical fiber connector and an adapter inthe prior art.

According to an embodiment of a still further aspect of the presentinvention, a monitoring device is provided which comprises at least oneoptical sensor assembly as described in the embodiments above and anOTDR (optical time domain reflectometer). The optical sensors of theoptical sensor assembly are respectively mounted to at least onemonitored object, such as an optical cross-connecting box anddistribution box. The optical time domain reflectometer is constructedto emit a main beam towards said optical sensors through the opticalcable transmission device of the optical sensor assembly and receive areflected beam reflected from said optical sensors, and the optical pathdistances between the optical time domain reflectometer and the opticalsensors are different from one another.

FIG. 12A shows a schematic view of a monitoring device 400 according toa first exemplary embodiment of the present invention. The monitoringdevice 400 comprises an optical sensor assembly and an optical timedomain reflectometer 406. The optical sensor assembly comprises theoptical sensors 100, 200 and 300 according to the present invention andan optical cable transmission device. The optical sensor 100 is mountedto an optical cross-connecting box arranged in a work site (such as anoffice building, residential building, open country or a hazardouslocation where people should keep away from), and the optical sensor isconfigured such that the actuation part 15 of the optical sensor ispressed when a door of the optical cross-connecting box is closed (oropened), so as to result in movement of the movable ferrule towards thefixed ferrule. The optical time domain reflectometer 406 emits a mainbeam towards the optical sensor 100 through the optical cabletransmission device 101 and receives a reflected beam reflected from theoptical sensor 100.

The monitoring device 400 of the first embodiment further comprises ashunt 408, which is constructed to split a detection beam out of themain beam from the optical time domain reflectometer 406, the detectionbeam being transmitted to an optical sensor assembly. More specifically,the optical time domain reflectometer 406 is optically connected withthe shunt 408 through a main optical cable transmission device 405.Furthermore, the main optical cable transmission device 405 comprisestwo optical fibers, of which one optical fiber is connected with theoptical time domain reflectometer 406 and the other optical fiber isconnected with a service network 407 to transmit communicationinformation to the optical cross-connecting box. Examples of the shuntcan include a PLC shunt, a circulator, or an equivalent shunt device.The shunt 408 comprises multiple optical channels, such as 16 or 32optical channels, wherein one optical channel 16 or optical channel 32is connected with the optical cable transmission device 101 connected toan optical sensor 100, for transmitting a detection beam and a reflectedbeam reflected from the optical sensor 100 while the other opticalchannels 1-15 or 1-31 are used for transmitting other opticalinformation signals.

The intensity of the reflected beam can be acquired at the optical timedomain reflectometer 406. FIG. 12B shows a curve diagram of the lightintensity acquired at an optical time domain reflectometer as a functionof distance when the monitoring device shown in FIG. 12A operates. Asshown in FIG. 12B, in the process of transmitting a beam in the opticalfiber and the shunt, the light intensity acquired at the optical timedomain reflectometer 406 decreases with the length of the optical fiber(i.e., the distance between the optical sensor and the optical timedomain reflectometer) or decreases due to passing through a highattenuation device such as the shunt.

When the door of the optical cross-connecting box is closed, theactuation part 15 of the optical sensor 100 is pressed, resulting in amovement of the movable ferrule 13 so that the first movable end of themovable ferrule 13 comes into contact with the first fixed end of thefixed ferrule 12 and, when the optical fiber hole 121 of the fixedferrule 12 contacts with the optical fiber hole 131 of the movableferrule 13, most of the detection beam from the fixed ferrule 12 isincident to the movable ferrule 13 and reflected back to the fixedferrule 12 by the reflection part 14. The reflected beam is furthertransmitted to the optical time domain reflectometer 406 and thereforethe light intensity acquired by the optical time domain reflectometer406 shows a pulsed jump; the optical time domain reflectometer 406further converts the change in light intensity into a change in electricsignal, so as to detect the closure of the door of the opticalcross-connecting box according to the change in electric signal.

Although an exemplary embodiment, in which an optical pulse can beacquired at the optical time domain reflectometer when the opticalcross-connecting box is closed, has been described as above, the presentinvention is not limited thereto. Those skilled in the art canunderstand that the optical sensor can be mounted such that theactuation part 15 is driven when the door of the opticalcross-connecting box is opened, to drive the movable ferrule 13 to movetowards the fixed ferrule, so that the generation of an optical pulsesignal is detected at the optical time domain reflectometer 406, so asto determine that the door of the optical cross-connecting box has beenopened. In a further alternative embodiment, when the optical sensor ismounted such that when the door is opened, the actuation part 15 drivesthe movable ferrule 13 to move away from the fixed ferrule due to theacting force of the reset device, a decreased or disappearing opticalpulse signal is detected at the optical time domain reflectometer 406,so as to determine that the door of the optical cross-connecting box hasbeen opened. It can be understood that the degree of opening of the doorof the optical cross-connecting box can be determined by using thechange in intensity of the optical pulse signal detected at the opticaltime domain reflectometer 406.

As shown in FIG. 17, an integrated management platform arranged in acentral machine room can monitor in real time the opening or closure ofthe door of the optical cross-connecting box. If the door of the opticalcross-connecting box is opened not for a normal reason, for exampleopened accidentally, or opened due to technical personnel or engineeringpersonnel forgetting to close it, or opened due to being impacted orstolen, the integrated management platform activates an automatic alarmplatform to send an alarm signal, for example, by using a mobileterminal alarm, audible and visual alarm, Web alarm, or other types ofalarms which can be sensed by related personnel.

FIG. 13A shows a schematic view of a monitoring device 500 according toa second exemplary embodiment of the present invention. The monitoringdevice 500 of the second embodiment is an improved embodiment over themonitoring device 500 of the first embodiment. The monitoring device 500of the second embodiment differs from the monitoring device 400 of thefirst embodiment in that three optical channels 14-16 or 30-32 of ashunt 508 are respectively connected to three optical sensor assemblies.The shunt 508 separates three detection beams out of a main beam from anoptical time domain reflectometer 506, each detection beam beingtransmitted to a corresponding optical sensor assembly. As such,multiple optical cross-connecting boxes (such as 3 opticalcross-connecting boxes) or multiple positions on one opticalcross-connecting box can be monitored using the monitoring device 500 ofthe second embodiment.

FIG. 13B shows a curve diagram of light intensity acquired at an opticaltime domain reflectometer as a function of distance when the monitoringdevice shown in FIG. 13A operates. As shown in FIG. 13B, the lightintensity acquired by the optical time domain reflectometer 406 showsmultiple pulsed jumps, each pulse corresponding to one optical sensor.The optical time domain reflectometer 406 further converts the change inlight intensity into a change in electric signal, so as to detect theopening of the door of the corresponding optical cross-connecting boxaccording to the change in electric signal.

FIG. 14A shows a schematic view of a monitoring device 600 according toa third exemplary embodiment of the present invention. The monitoringdevice 600 is an improved embodiment over the monitoring device 400 ofthe first embodiment. The monitoring device 600 of the third embodimentdiffers from the monitoring device 400 of the first embodiment in that asplitter 604 is arranged behind the shunt 608. Examples of the splitterinclude a 1×4 splitter (i.e., splitting a light input signal into 4branches to output), and a 1×8 splitter. The splitter 604 is in opticalcommunication with the optical channel 16 or 32 of the shunt 608, forsplitting a detection beam from the optical channel 16 or 32 into 4detection sub-beams, each detection sub-beam being transmitted to thecorresponding optical sensor assembly. Thus, multiple opticalcross-connecting boxes (such as 3 optical cross-connecting boxes) ormultiple positions on one optical cross-connecting box can be monitoredusing the monitoring device 600 of the third embodiment.

FIG. 14B shows a curve diagram of light intensity acquired at an opticaltime domain reflectometer as a function of distance when the monitoringdevice shown in FIG. 14A operates. As shown in FIG. 14B, the lightintensity acquired by an optical time domain reflectometer 606 showsmultiple pulsed jumps, each pulse corresponding to one optical sensor.The optical time domain reflectometer 606 further converts the change inlight intensity into a change in electric signal, so as to detect theopening of the door of the corresponding optical cross-connecting boxaccording to the change in electric signal.

FIG. 15A shows a schematic view of a monitoring device 700 according toa fourth exemplary embodiment of the present invention. The monitoringdevice 700 is an improved embodiment over the monitoring device 600 ofthe third embodiment. The monitoring device 700 of the fourth embodimentdiffers from the monitoring device 600 of the third embodiment in thatthere are multiple groups of monitored objects and one optical switch703 is provided, for example each group of monitored objects is arrangedin one region. Examples of the optical switch can include a wavelengthdivision multiplexer or equivalent multiplexing device. In themonitoring device 700, one shunt 708 and at least one optical sensorassembly are arranged for each group of monitored objects and,correspondingly, an optical fiber for transmitting a detection beam in amain optical cable transmission device 705 is divided into multipleoptical sub-fibers, each optical sub-fiber being optically connectedwith one corresponding shunt 704. The optical switch 703 is constructedto control one of the multiple shunts to come into an operating state,that is, during one time period, only one shunt 704 is in the operatingstate and the optical sensor corresponding to the shunt in the operatingstate has a detection beam, while the other shunts are in an idle stateand no detection beam is present in the optical sensors corresponding tothe idle shunts. Therefore, the curve diagram shown in FIG. 15B of lightintensity acquired at an optical time domain reflectometer as a functionof distance when the monitoring device 700 of the fourth embodimentoperates is substantially the same as the curve diagram shown in FIG.14B of light intensity acquired at an optical time domain reflectometeras a function of distance when the monitoring device 600 of the thirdembodiment operates.

FIG. 16A shows a schematic view of a monitoring device 800 according toa fifth exemplary embodiment of the present invention. The monitoringdevice 800 of the fifth embodiment comprises at least multiple opticalsensor assemblies as described in the embodiments above and an opticaltime domain reflectometer. The optical sensors of the optical sensorassemblies are respectively mounted to at least one monitored object,such as an optical cross-connecting box and distribution box. Themonitored objects are divided into multiple groups; for example, eachgroup of monitored objects is arranged in one region, and at least oneoptical sensor assembly is arranged for each group of monitored objects.

The monitoring device 800 of the fifth embodiment further comprisesmultiple splitters 808 connected in series, each splitter 808 splits adetection beam from a previous stage into a main detection beam and adetection sub-beam, and each splitter 808 is arranged in a propagationpath of the detection main beam and each optical sensor 101 receives thecorresponding detection sub-beam.

Furthermore, the light flux ratio of the main detection beam anddetection sub-beam output from each splitter 808 is 20:80-1:99.

FIG. 16B shows a curve diagram of light intensity acquired at an opticaltime domain reflectometer as a function of distance when the monitoringdevice 800 shown in FIG. 16A operates. As shown in FIG. 16B, the lightintensity acquired by the optical time domain reflectometer 806 showsmultiple pulsed jumps, each pulse corresponding to one optical sensor.The optical time domain reflectometer 806 further converts the change inlight intensity into a change in electric signal, so as to detect theopening of the door of the corresponding optical cross-connecting boxaccording to the change in electric signal.

FIG. 17 shows a schematic block diagram of a monitoring system formonitoring multiple monitored points using the monitoring device of thepresent invention. As shown in FIG. 17, the mechanical state of onemonitored object (such as monitored objects A-Z), multiple monitoredpoints of one monitored object (such as monitored points A-Z ofmonitored object A), or multiple groups of monitored objects can bemonitored using the monitoring device of the present invention based onoptical sensors.

An on-site optical cross-connecting box can be taken as a monitoredobject when using the monitoring devices of the embodiments of thepresent invention. However, the present invention is not limited to thisand it can be understood that any equipment which can drive theactuation part of the present invention to move can be used as amonitored object for the monitoring device of the present invention,such as a distribution box, an outdoor transformer box body, a floodwall gate, a manhole cover, and various objects with open/closeoperation, such as tanks arranged in hazardous locations where peopleshould keep away from.

Referring now additionally to FIGS. 18-30, this disclosure relates toremote monitoring of passive optical network elements, based on thereflected power at certain discrete points along an optical fiber. FIG.18 illustrates an example of a sensor system in accordance with aspectsof the present disclosure. The illustrated sensor system 1010 includes asensor 1012 coupled to an optical fiber 1014 and a reflector 1016. Thereflector 1016 is configured to provide a reflected optical signal.Power can be reflected by metal coated fibers, Thin Film Filters (TFF)or Bragg grating devices, for example.

In certain embodiments of the illustrated sensor system 1010, the sensor1012 is situated in an enclosure 1100 such as an equipment cabinet. Thereflected power is intensity modulated in response to a parameter 1018associated with the enclosure 1100, such as moisture in the enclosure,enclosure temperature, intrusion into the enclosure, etc. Thesemodulated reflections can be detected with a conventional opticaltime-domain reflectometer (OTDR). An OTDR is an optoelectronicinstrument used to characterize an optical fiber. Optical pulses areinjected into an end of the optical fiber 1014, and light reflected backfrom points along the fiber 1014 is extracted from the same end of thefiber 1014 and analyzed. The strength of the return pulses is measuredas a function of time, and is plotted as a function of fiber length.Embodiments of the disclosed sensor system thus provide a fully passiveoptical sensor system (no electricity or battery required at themonitored enclosure).

In the example of FIG. 18, a dedicated optical fiber 1014 is providedfor monitoring parameters of the enclosure 1100. FIG. 19 illustrates anexample that includes a fiber optic tap 1020 that provides a connectionto the sensor 1012. In some implementations, a multiplexing scheme, suchas wavelength division multiplexing (WDM), is used to allow the samefiber 1014 to be used both for monitoring and for communications.

FIG. 20 illustrates an implementation where three tap couplers 1020 arecoupled to the fiber 1014 to connect to three sensors in respectiveenclosures 1100 a, 1100 b, 1100 c. The optical fiber 1014 is coupled toan OTDR 1030 that receives light reflected from the reflectors 1016associated with the sensors 1012 for each of the enclosures 1100 a, 1100b, 1100 c. FIG. 21 illustrates an example of the return pulses plottedas a function of distance, thus providing a pulse 1022 a, 1022 b, 1022 ccorresponding to each of the enclosures 1100 a, 1100 b, 1100 c.

The OTDR may further be connected to a monitoring system 1050 thatprovides information regarding the monitored enclosures, alarms, datalogging, etc. The monitoring system 1050 could be implemented by anysuitable computing system. In some examples, the monitoring system 1050includes an appropriately programmed processor configured to executevarious processes for analyzing the OTDR signals. A system memory storesan operating system for controlling the operation of the monitoringsystem.

The system memory is computer-readable media. Examples ofcomputer-readable media include computer storage media and communicationmedia. Computer storage media is physical media that is distinguishedfrom communication media. Computer storage media includes physicalvolatile and nonvolatile, removable and non-removable media implementedin any method or technology for persistent storage of information, suchas computer-readable instructions, data structures, program modules, orother data. Computer storage media also includes, but is not limited to,RAM, ROM, EEPROM, flash memory or other memory technology, CD-ROM, DVDor other optical storage, magnetic cassettes, magnetic tape, magneticdisk storage or other magnetic storage devices, or any other mediumwhich can be used to persistently store desired information and whichcan be accessed by the monitoring system 1050. Any such computer storagemedia may be part of or external to the monitoring system 1050.

Communication media is typically embodied by computer-readableinstructions, data structures, program modules, or other data, in amodulated data signal, such as a carrier wave or other transportmechanism, and includes any information delivery media. The term“modulated data signal” means a signal that has one or more of itscharacteristics set or changed in such a manner as to encode informationin the signal. By way of example, communication media includes wiredmedia such as a wired network or direct-wired connection, and wirelessmedia such as acoustic, RF, infrared and other wireless media.

The monitoring system 1050 may further include one or more input andoutput devices, such as a keyboard, mouse, a display, etc. Themonitoring system 1050 can be connected to the OTDR 1030 and othercomputing devices via a network that provides a data communication pathfor data transfer between the OTDR 1030 and the monitoring system 1050.

FIGS. 22A, 22B and 22C illustrate examples of various configurations formonitoring enclosures, such as telecommunications equipment cabinets.Each enclosure 1100 includes an enclosure housing 1102 and one or moredoors 1104 that are movable relative to the housing 1102 to give accessto the inside of the enclosure 1100. Each enclosure 1100 has a sensorsystem 1010 associated therewith that is connected to an optical fiber1014. In FIG. 22A, the enclosure 1100 includes a single door 1104, and acorresponding sensor system 1010 that monitors intrusion, for example,by attenuating the signal reflected by the reflector 1016 in response tothe door 1104 opening. FIG. 22B illustrates an alternative arrangementwhere two doors 1104 are provided with corresponding intrusion sensors1010. FIG. 22C illustrates another alternative arrangement that includestwo doors 1104, with a single sensor 1010 that is responsive to eitherof the doors 1104 opening. Of course many other arrangements arepossible.

FIGS. 23 and 24 conceptually illustrates an example of the sensor 1010in first and second positions, respectively, where the second positionis configured to attenuate the reflected optical signal more than thefirst position. The sensor 1010 is configured to move between the firstand second positions in response to the monitored parameter 1018.

FIG. 23 illustrates the sensor 1010 in the first, or open position. Inthe examples disclosed above in conjunction with FIGS. 22A-22C, thesensor 1010 functions as an intrusion monitor that senses the cabinetdoor 1104 opening. In some implementations, the sensor system 1010 alsoconfirms secure closure of the door 1104. The sensor 1012 includes firstand second parts 1012 a, 1012 b. In intrusion monitoringimplementations, the sensor 1012 is situated in the first position(first and second parts 1012 a, 1012 b spaced apart) by any suitablepositioning device, such as a spring. An example of the positioningmechanism is discussed further below. The sensor is based onmacrobending, with the first and second parts 1012 a, 1012 b includingan inner surface defining one or more bends or curves, each with aradius R of 3 to 5 mm in some implementations. In the illustratedembodiment, the inner surfaces of the first and second parts 1012 a,1012 b each have a plurality of the radiused bends. For example, matchedcladding G652 fiber is provided with a straight, cleaved end with a goldplated fiber end or Bragg grating to implement the reflector 1016.

The sensor 1012 is situated in the first position when the door 1104 isclosed. In the open position illustrated in FIG. 23, the first andsecond parts 1012 a, 1012 b are spaced apart by a first distance suchthat a light path 1031 is provided between the first and second sensorparts 1012 a, 1012 b that minimally attenuates both the incoming light1032 and reflected light 1034.

FIG. 24 illustrates the sensor system 1010 in the second position, wherethe first and second parts 1012 a, 1012 b are moved closer to oneanother such that they are spaced apart by a second distance in responseto the monitored parameter 1018. In the illustrated example, themonitored parameter 1018 is enclosure intrusion, so when the cabinetdoor 1104 is opened, the first and second parts 1012 a, 1012 b movecloser together and deform the fiber 1014, which attenuates thereflected signal more than it is attenuated when in the first positionshown in FIG. 23. In some embodiments, the fiber deformation results inattenuation of about 3 to 5 dB at 1625 nm. Accordingly, the power of thereflected light 1034 reaching the OTDR is reduced. Of course other waysand devices for attenuating the reflected signal are possible and wouldbe evident to one of ordinary skill in the art having the benefit ofthis disclosure. For example, the optical fiber could be bent varyingamounts to correspondingly vary attenuation, or the fiber could belooped and the radius of the loop varied. Further, the first position ofthe sensor could be associated with the door open and the secondposition with the door closed, wherein the opening of the door will thenresult in an increased reflection.

For a configuration such as the example illustrated in FIGS. 23 and 24,the minimum recommended dynamic range of the OTDR is 35 dB (at 1625 nm)in order to “see” the reflected pulse. This can be calculated as in thefollowing example:

2×{20 km Length fiber (5 dB)}+Loss of 1×64 splitter (20.5 dB)+loss APCconnector (0.5 dB)}+reflection from cleaved fiber (15 dB)=67 dB

-   -   (Note: the 35 dB dynamic range of the OTDR corresponds with a        physical 2×35 dB=70 dB dynamic range.)

FIG. 25 illustrates example OTDR pulses 1022 where the door of thesecond enclosure 1100 b (referring to FIG. 20) is opened. Prior to thedoor 1104 opening, the sensor system 1010 associated with the enclosure1100 b is in the first position (FIG. 23), and the OTDR pulse 1022 b hasa first height h1 as shown in FIG. 21. When the door 1104 of enclosure1100 b opens, the corresponding sensor system 1010 moves from the firstposition (FIG. 23) to the second position (FIG. 24), attenuating thereflected optical signal. Thus, the OTDR pulse 1022 b is reduced to asecond height h2 as shown in FIG. 25, noting an intrusion into thecabinet 1100 b.

FIG. 26 conceptually illustrates an example of the sensor system 1010configured to monitor the parameter of enclosure intrusion. A pigtail1112 extends between a fiber optic connector 1114, such as an APCconnector, and a shell 1110 of the sensor 1010. The fiber 1014 extendsinto the shell 1110, between the first and second sensor parts 1012 a,1012 b with the reflector 1014 at the fiber end. As noted in conjunctionwith the description of FIGS. 23 and 24, the sensor parts 1012 a, 1012 bare situated normally in the first position (open) for enclosureintrusion implementations. In the example shown in FIG. 26, the firstpart 1012 a is movable relative to the second part 1012 b. A positioningmember, such as a spring 1116 is situated between the shell 1110 and thefirst sensor part 1012 a to push the first part 1012 a towards thesecond part 1012 b. Two legs extend from the first sensor part 1012 a toform an actuator 1118. The sensor 1010 is positioned in the enclosure1100 such that the actuator 1118 is in contact with the enclosure door1104, so when the door 1104 is closed it pushes the actuator 1118 andthus, the first sensor part 1012 a away from the second sensor part 1012b to situate the first and second parts 1012 a, 1012 b in the firstposition when the door 1104 is closed. When the door 1104 is opened, itmoves away from the actuator 1118 allowing the spring 1116 to push thefirst sensor part 1012 a towards the second sensor part 1012 b,positioning the sensor 1010 in the second position so as to attenuatethe OTDR signal in the manner shown and described in conjunction withFIG. 24.

The sensing system 1010 may be used in enclosures deployed in harshenvironments. For such implementations, a hardened sensing system 1010may be provided, where the sensor parts 1012 and reflector 1016 aresituated in a shell 1110 having an Ingress Protection (IP) Rating of atleast IP55 (dust protected and water jet protected), and the sensingsystem 1010 is functional for 500 cycles in a temperature range of −40°C. to +65° C., for example.

FIG. 27 illustrates aspects of an example of another version of thesensor system 1010 that uses a comparison of the amplitude of tworeflected pulses—a reference pulse and a modulated pulse. If the OTDRpulse is compared to the signal baseline for analysis purposes,sometimes analysis errors can occur. For example, in long lines or ifsplices or connectors are not stable, the baseline signal can becomenoisy, making it difficult to compare the OTDR pulse with the baseline.This can result in false alarms.

As illustrated in FIG. 27, a 1:2 fiber optic splitter 1040 has a firstterminal connected to the sensor 1012 via a delay device 1042. First andsecond reflectors 1016, 1017 are provided, with the first reflector 1016being coupled to the sensor 1012 as described above. Due to the timedelay device 1042, the first reflector provides a time-delayed reflectedoptical signal. The reflectors 1016, 1017 can be implemented by goldplated fiber ends or Bragg grating, for example. The second reflector1017 provides a second (reference) reflected optical signal, which iscompared to the time-delayed signal from the first reflector 1016 thatis attenuated by the sensor 1012 based on the monitored parameter 1018.In other implementations, the delay loop can be connected between thesecond reflector 1017 and the splitter 1040.

FIG. 28 illustrates the OTDR pulses 1022, 1023 for the first and secondreflectors 1016, 1017, respectively. As described above, the sensor 1012attenuates the first reflected signal 1012 based on the monitoredparameter 1018. By comparing the second, or reference, signal 1023 tothe time delayed sensor signal 1022, an indication of the monitoredparameter 1018 can be obtained. The difference between the first andsecond OTDR pulses 1022, 1023 is shown in FIG. 28 as Δh. For instance,for the example described above where enclosure intrusion is themonitored parameter, the sensor 1012 is in the first position when theenclosure door is closed. In the first position, the optical signalreflected by the reflector 1014 is not attenuated (or attenuated lessthan when in the second position), resulting in a first value for Δh. Ifthe monitored parameter causes the sensor 1012 to attenuate thereflected signal, the height of the first OTDR pulse 1022 will change ascompared to the second OTDR pulse 1023, causing the value of Δh tochange and provide an indication of the monitored parameter. Using theΔh signal to monitor the parameter 1018 makes the sensor systemmeasurements independent from other optical losses over the line betweenthe sensor system 1010 and the OTDR. Thus, recalibration is not requiredafter making changes to the network, such as splices or addingadditional components.

In certain implementations, the sensing system 1010 illustrated in FIG.27 is used in a configuration such as that shown in FIG. 20. Referringto FIGS. 20 and 27, such an implementation includes a plurality ofenclosures, each with a sensor system 1010, coupled to the optical fiber1014 via the taps 1020. A plurality of the first reflectors 1016 areeach connected to a corresponding one of the sensors 1012. A pluralityof the second reflectors 1017 are further provided, corresponding toeach of the sensors 1012.

FIG. 29 illustrates another example where a plurality of parameters(temperature, water, humidity, intrusion) can be monitored for the sameenclosure 1100 or at a single location using a single optical fiber1014. A fiber optic tap 1020 is coupled to an optical fiber 1014 and toa 1:4 splitter 1041, which is connected to plurality of sensor systems1010 a, 1010 b, 1010 c. As disclosed above, each of the sensor systems1010 includes sensor parts 1012 and a corresponding first reflector 1016as shown, for example, in FIGS. 23 and 24. Each of the sensors 1010 a,1010 b, 1010 c is connected to the splitter 1040 via a correspondingtime delay device such as delay loops 1042 a, 1042 b, 1042 c, with eachdelay loop having a different length to delay the OTDR signal adifferent time period for each reflected signal. The second reflector1016 is further coupled to the splitter 1040 to provide a referencesignal. In some implementations, each sensor monitors a differentparameter 1018 a, 1018 b, 1018 c. A comparison of the reflected opticalsignals from each of the sensors 1010 a, 1010 b, 1010 c to the secondoptical signal from the reference reflector 1017 provides an indicationof the plurality of monitored parameters.

For example, the sensor system 1010 could monitor three doors of asingle enclosure, or a variety of other parameters such as humidity,intrusion and temperature for a single enclosure. Humidity or moisturesensors could be formulated using a material that swells or expands inresponse to moisture. As the material swells, it presses an opticalfiber in a “sawtooth” cavity or a cavity with radiused curves similar tothat shown in FIGS. 23 and 24. A temperature sensor can be formed usinga bi-metal structure that similarly deforms s fiber in response totemperature variation.

FIG. 30 illustrates examples of various OTDR signals generated by thesystem shown in FIG. 29. The pulse 1023 is the reference pulse from thereflector 1017, and the other three pulses 1024 a, 1024 b, 1024 ccorrespond to the signals reflected from the reflectors associated withthe sensors 1010 a, 1010 b, 1010 c. As noted above, each of the sensors1010 a, 1010 b, 1010 c is coupled to the splitter 1040 via a respectivedelay loop 1042 a, 1042 b, 1042 c, so the OTDR pulses associated withthe respective sensors are spaced along the distance axis. Comparingeach of the sensor pulses 1024 a, 1024 b, 1024 c to the reference pulse1023 results in a corresponding Δh signal, Δha, Δhb, Δhc. When themonitored parameter 1018 changes, it results in the respective sensorattenuating the reflected signal, which in turn changes the pulse heightas compared to the reference pulse 1023.

Those skilled in the art can understand that the embodiments describedabove are exemplary and can be improved by those skilled in the art, andthat the structures described in the embodiments can be freely combinedwithout producing a conflict in terms of structure or principles, so asto realize more types of optical sensors, optical sensor assemblies andmonitoring devices while solving the technical problems of the presentinvention.

After the preferred embodiments of the present invention have beendescribed in detail, those skilled in the art can clearly understandthat various changes and modifications can be made without departingfrom the protective scope and spirit of the appended claims and theinvention is also not limited to the practice of the exemplaryembodiments set forth in the description.

PARTS LIST

-   11 holding sleeve-   12 fixed ferrule-   13 movable ferrule-   14 reflection part-   15 actuation part-   16 reset device-   17 limiting part-   21 holding sleeve-   22 fixed ferrule-   23 movable ferrule-   24 reflection part-   25 actuation part-   26 reset device-   27 main body frame-   28 guide frame-   29 housing-   31 holding sleeve-   32 fixed ferrule-   33 movable ferrule-   34 reflection sleeve-   35 actuation part-   36 reset device-   37 main body frame-   38 guide frame-   39 housing-   100 optical sensor-   101 optical cable transmission device-   102 optical cable-   103 first optical fiber connector-   121 optical fiber hole-   131 optical fiber hole-   200 optical sensor-   221 device-   251 limiting part-   252 guide protrusion-   271 base part-   272 sleeve holder-   273 extension arm-   274 engagement protrusion-   281 end part-   282 hole-   283 guide groove-   284 engagement groove-   285 positioning frame-   291 mounting part-   292 mounting hole-   300 optical sensor-   391 flexible connection part-   400 monitoring device-   405 main optical cable transmission device-   406 optical time domain reflectometer-   407 service network-   408 shunt-   500 monitoring device-   506 optical time domain reflectometer-   508 shunt-   600 monitoring device-   604 splitter-   606 optical time domain reflectometer-   608 shunt-   700 monitoring device-   703 one optical switch-   704 one shunt-   705 main optical cable transmission device-   706 optical time domain reflectometer-   708 one shunt-   800 monitoring device-   806 optical time domain reflectometer-   808 multiple splitters-   1010 sensor system-   1012 sensor-   1012 a first sensor part-   1012 b second sensor part-   1014 optical fiber-   1016 reflector-   1017 second reflector-   1018 parameter-   1018 a parameter-   1018 b parameter-   1018 c parameter-   1020 fiber optic tap coupler-   1022 pulse-   1022 a pulse-   1022 b pulse-   1022 c pulse-   1023 pulse-   1024 pulse-   1024 a pulse-   1024 b pulse-   1024 c pulse-   1030 OTDR-   1031 light path-   1032 incoming light-   1034 reflected light-   1040 fiber optic splitter-   1042 delay device-   1042 a delay loops-   1042 b delay loops-   1042 c delay loops-   1050 monitoring system-   1100 enclosure-   1100 a enclosure-   1100 b enclosure-   1100 c enclosure-   1102 enclosure housing-   1104 door-   1110 shell-   1112 pigtail-   1114 fiber optic connector-   1116 spring-   1118 actuator

What is claimed is:
 1. An optical sensor (100, 200, 300), comprising: aholding sleeve (11); a fixed ferrule (12) fixedly mounted in saidholding sleeve; a movable ferrule (13) movably mounted in said holdingsleeve, a predetermined distance existing between a first movable end ofsaid movable ferrule and a first fixed end of said fixed ferrule in saidholding sleeve; a reflection part (24) arranged at a second movable endof said movable ferrule opposite to said first movable end, forreflecting light entering the movable ferrule; and an actuation part(15), said actuation part being constructed to drive said movableferrule to move so that said first movable end moves towards said firstfixed end.
 2. The optical sensor of claim 1, further comprising a resetdevice (16), wherein said actuation part drives said movable ferrule tomove against the force of said reset device.
 3. The optical sensor ofclaim 1, wherein the reflection part is a reflection face formed on thesecond movable end of said movable ferrule.
 4. The optical sensor ofclaim 1, wherein said reflection face provides a reflectioncharacteristic independent of wavelength.
 5. The optical sensor of claim1, wherein said reflection face provides a selective waveband reflectioncharacteristic dependent on wavelength.
 6. The optical sensor of claim1, wherein said reflection part is formed on said actuation part and isin sealed connection with said second movable end.
 7. The optical sensorof claim 1, wherein a limiting part (17) is arranged on one of saidmovable ferrule and the actuation part, said limiting part beingconstructed to limit the distance of movement of said movable ferrule.8. The optical sensor of claim 1, wherein the end surfaces of said firstfixed end and said first movable end are constructed to be parallel witheach other and form an angle relative to an axis of the holding sleeve.9. The optical sensor of claim 8, wherein the end surfaces of said firstfixed end and said first movable end are inclined by 5°-10° relative tothe axis of the holding sleeve.
 10. The optical sensor of any one ofclaims 2-9, further comprising: a main body frame (27), said holdingsleeve being arranged in said main body frame; and a guide frame (28)mounted on said main body frame, said actuation part being movablymounted on said guide frame.
 11. The optical sensor of claim 10, whereinsaid actuation part is provided with a guide protrusion (252) and saidguide frame is provided with a guide groove (283) matching with saidguide protrusion.
 12. The optical sensor of claim 10, further comprisinga housing (39), said main body frame being mounted in said housing. 13.The optical sensor of claim 12, further comprising a positioning frame(285) mounted between said housing and said guide frame.
 14. The opticalsensor of claim 12, wherein said housing is connected to said actuationpart through a flexible connection part, so that said flexibleconnection part moves with said actuation part.
 15. An optical sensorassembly, comprising: an optical sensor (100, 200, 300) of any one ofclaims 1-14; and an optical cable transmission device, constructed to beoptically coupled to a second fixed end of said fixed ferrule, fortransmitting light incident to said fixed ferrule and light reflectedfrom said reflection part.
 16. The optical sensor assembly of claim 15,wherein a first end of an optical cable of said optical cabletransmission device is provided with a first optical fiber connector,and a second end of the optical cable of said optical cable transmissiondevice is directly optically coupled with the second fixed end of saidfixed ferrule.
 17. The optical sensor assembly of claim 15, wherein afirst end of an optical cable of said optical cable transmission deviceis provided with a first optical fiber connector, and a second end ofthe optical cable of said optical cable transmission device is opticallycoupled with the second fixed end of said fixed ferrule through a secondoptical fiber connector.
 18. A monitoring device (400, 500, 600, 700,800), comprising: at least one optical sensor assembly of any one ofclaims 15-17, the optical sensors of said optical sensor assembly beingrespectively mounted to at least one monitored object; and an opticaltime domain reflectometer (406, 506, 606, 706, 806), constructed to emita main beam towards said optical sensors through the optical cabletransmission device of the optical sensor assembly and receive areflected beam reflected from said optical sensors, the optical pathdistances between said optical time domain reflectometer and the opticalsensors being different from one another.
 19. The monitoring device ofclaim 18, further comprising: a shunt, constructed to separate at leastone detection beam out of the main beam from said optical time domainreflectometer, each detection beam being transmitted to a correspondingoptical sensor assembly.
 20. The monitoring device of claim 19, furthercomprising a splitter constructed to split said detection beam intomultiple detection sub-beams, each detection sub-beam being transmittedto a corresponding optical sensor assembly.
 21. The monitoring device ofclaim 20, wherein said monitored objects are divided into multiplegroups, and one shunt and at least one optical sensor assembly arearranged for each group of monitored objects, and said monitoring devicefurther comprises an optical switch constructed to control one of saidshunts to enter an operating state.
 22. The monitoring device of claim18, wherein said monitored objects are divided into multiple groups, andat least one optical sensor assembly is arranged for each group ofmonitored objects, and said monitoring device further comprises multiplesplitters connected in series, each splitter splitting a detection beamfrom a previous stage into a main detection beam and a detectionsub-beam, and each splitter being arranged in a propagation path of thedetection main beam, each optical sensor receiving a correspondingdetection sub-beam.
 23. The monitoring device of claim 22, wherein thelight flux ratio of the main detection beam and the detection sub-beamoutput from each splitter is 20:80-1:99.
 24. The monitoring device ofclaim 18, wherein the monitored object includes a field opticalcross-connecting box.
 25. A sensor system, comprising: a first reflector(14, 1016) configured to provide a first reflected optical signal(1022); a sensor (100, 1012) having a first position and a secondposition, the second position configured to attenuate the firstreflected optical signal more than the first position, the sensor beingconfigured to move between the first and second positions in response toa monitored parameter (15, 1018); wherein a change in the attenuation ofthe first reflected optical signal provides an indication of themonitored parameter.
 26. The sensor system of claim 25, furthercomprising: a second reflector (1017) configured to provide a secondreflected optical signal (1023); wherein a comparison of the first andsecond reflected optical signals provides an indication of the monitoredparameter.
 27. The sensor system of claim 26, further comprising a timedelay device (1042) connected to either the sensor (1012) or the secondreflector (1017).
 28. The sensor system of any of the preceding claims,further comprising an optical time-domain reflectometer (OTDR) (406,506, 606, 708, 806, 1030) configured to receive the reflected opticalsignals.
 29. The sensor system of any of the preceding claims, furthercomprising: an optical fiber (101, 1014); a plurality of the sensors(100, 1012); a plurality of the first reflectors (14, 1016), each of thefirst reflectors having a corresponding one of the sensors; a pluralityof fiber optic taps (1020), each of the fiber optic taps coupled to theoptical fiber and a corresponding sensor and first reflector.
 30. Thesensor system of any of the preceding claims, further comprising: anoptical fiber (101, 1014); a plurality of the sensors (100, 1012); aplurality of the first reflectors (24, 1016) configured to provide aplurality of the first reflected optical signals (1022), each of thefirst reflectors having a corresponding one of the sensors; a pluralityof time delay devices (1042); a fiber optic splitter (1040) arranged tocouple the optical fiber to each of the sensors and first reflectors viaa corresponding one of the time delay devices; and wherein a change inthe attenuation of the first reflected optical signals provides anindication of the corresponding monitored parameter.
 31. The sensorsystem of any of the preceding claims, wherein: the sensor includesfirst and second parts (12, 13, 1012 a, 1012 b); the first and secondparts are spaced apart by a first distance when in the first position;and the first and second parts are spaced apart by a second distanceless than the first distance when in the second position.
 32. The sensorsystem of claim 31, wherein the first and second parts each include aninner surface defining a radius (R).
 33. The sensor system of any of thepreceding claims, wherein the first and second parts each include aferrule and at least one of the ferrules is moveable toward the otherferrule.
 34. An enclosure system, comprising: an enclosure housing(1102); a sensor system associated with the enclosure housing, thesensor system including: a first reflector (14, 1016) configured toprovide a first reflected optical signal; a sensor (100, 1012) having afirst position and a second position, the second position configured toattenuate the first reflected optical signal more than the firstposition, the sensor being configured to move between the first andsecond positions in response to a monitored parameter (1018); wherein achange in the attenuation of the first reflected optical signal providesan indication of the monitored parameter.
 35. The enclosure system ofclaim 34, further comprising: a second reflector (1017) configured toprovide second reflected optical signal (1023); wherein the firstreflected signal is time-delayed; and wherein a comparison of the firstand second reflected optical signals provides an indication of themonitored parameter.
 36. The enclosure system of any of claim 34 or 35,further comprising: a door (1104) that is movable relative to theenclosure housing (1102); wherein the sensor system is configured tomove from one of the first or second position to the other position inresponse to moving the door.
 37. The enclosure system of any of claims34-36, further comprising: a shell (29, 1110), wherein the sensor systemincludes first and second parts (12, 13, 1012 a, 1012 b) that aresituated in the shell such that the first part is movable relative tothe second part; and an actuator (15, 1118) configured to move the firstpart towards the second part in response to the door opening.
 38. Theenclosure system of claim 36, further comprising: a positioning member(16, 1116) situated between the shell (1110) and the first part (1012a).
 39. The enclosure system of any of claims 34-38, further comprising:a plurality of the sensors (100, 1012); a plurality of the firstreflectors (14, 1016) configured to provide a plurality of thetime-delayed first reflected optical signals (1022), each of the firstreflectors having a corresponding one of the sensors; wherein a changein the attenuation of the first reflected optical signals provides anindication of the corresponding monitored parameter (1018).
 40. Theenclosure system of claim 35, further comprising: a plurality of thesensors (100, 1012); a plurality of the first reflectors (14, 1016)configured to provide a plurality of the time-delayed first reflectedoptical signals (1022), each of the first reflectors having acorresponding one of the sensors; wherein a comparison of the pluralityof the time-delayed first reflected optical signals (1022) and thesecond reflected optical signal (1023) provides an indication of aplurality of monitored parameters (1018).
 41. The enclosure system ofany of claims 34-40, further comprising: a plurality of the enclosurehousings (1102); a plurality of the sensor systems (1010), each of theenclosure housings having at least one of the sensor systems associatedtherewith; an optical fiber (1014); a plurality of fiber optic taps(1020), each of the fiber optic taps coupled to the optical fiber and acorresponding sensor system.
 42. The enclosure system of any of claims34-41, further comprising: an OTDR (1030) connected to the opticalfiber.
 43. A method of monitoring an enclosure, comprising: providing afirst reflected optical signal (1022) from an enclosure (1100); changingthe attenuation the first reflected optical signal in response to amonitored parameter (1018); and monitoring the attenuation of the firstreflected optical signal.
 44. The method of claim 41, furthercomprising: providing a second reflected optical signal (1023) from theenclosure; time delaying one of the first or second reflected opticalsignals; comparing the first and second reflected optical signals toobtain an indication of the monitored parameter.
 45. The method of anyof claim 43 or 44, further comprising: providing a sensor system havingfirst and second parts (12, 13, 1012 a, 1012 b), the first part beingmovable relative to the second part; and moving the first part towardsthe second part to attenuate the first reflected optical signal (1022).46. The method of any of claims 43-45, wherein the monitored parameteris enclosure intrusion, the method further comprising: moving the firstpart (13, 1012 a) towards the second part (12, 1012 b) to attenuate thefirst reflected optical signal (1022) in response to a door (1104) ofthe enclosure housing (1102).
 47. The method of claim any of claims43-46, further comprising: providing a plurality of the first reflectedoptical signals (1022) from the enclosure, each of the first reflectedoptical signals corresponding to a monitored parameter (1018) timedelaying each of the first reflected optical signals by a different timeperiod; attenuating the first reflected optical signals in response tothe corresponding monitored parameters; comparing each of the firstreflected optical signals (1022) to the second reflected optical signal(1023) to obtain indications of the monitored parameters.
 48. The methodof any of claims 44-47, further comprising: providing a plurality of thefirst reflected optical signals (1022) from a corresponding plurality ofenclosures (1100); and providing a plurality of the second reflectedoptical signals (1023) from the corresponding plurality of enclosures.49. The method of any of claims 43-48, wherein the monitored parameter(1018) includes at least one of enclosure intrusion, temperature, water,and humidity.